Portable objects, such as remote transmitters used to control appliances (e.g., televisions, video recorder and stereo equipment), cellular phones, hand-held computers, pagers and car keys are often misplaced. For example, a remote transmitter may be lost in a room that the appliance it controls is located. The remote transmitter may easily fall behind a cushion of a sofa or chair, under a bed, or on top of a dresser, making the transmitter difficult to find.
One conventional method of preventing the loss of a portable electronic device is to secure the device in a holder and/or to an elastic band permanently mounted to a fixed structure, such as an end table near a bed in a motel or hotel room. This method is often used as an attempt to prevent theft or misplacement of the device, but is inconvenient to a user who desires the flexibility to remotely control an appliance from any various locations.
Another conventional method of preventing the loss of a portable electronic device is to incorporate an audible detector into the device that activates in response to a predetermined sequence of sound signals, such as those generated by hand claps, see, for example, U.S. Pat. No. 5,677,675 (Taylor et al.); a voice command included in a radio frequency carrier signal, see, for example, U.S. Pat. No. 6,012,029 (Cirino et al.); or other transmitted signals, see, for example, U.S. Pat. No. 6,501,378 (Knaven).
Another conventional method enables a portable electronic device to be located when the ambient light in the vicinity of the device is simply reduced below a predetermined level. See, for example U.S. Patent Application Publication No. 2003/0001738 (Chandar).
Unfortunately, some of the conventional methods described above are not reliable because they are subject to false alarms which cause the portable electronic device to emit an audible location signal prematurely. What is desired is a method and apparatus for locating an object that insures that an audible alert signal is emitted only when it is determined that the object is truly lost.
The present invention is an apparatus and method for locating an object only when a specific predetermined command is received.
In one embodiment, an apparatus for locating an object includes an ambient light sensor circuit and an alarm circuit in communication with the ambient light sensor circuit. The ambient light sensor circuit detects the occurrence of a plurality of transitions between a first light level and a second light level. The ambient light sensor circuit determines if a time period between at least some of the transitions is less than a predetermined value. An alarm circuit in communication with the ambient light sensor circuit emits an alert signal if the time period is less than the predetermined value.
The predetermined value may be about 500 milliseconds. The apparatus may be fastened to the object or incorporated into the object. The alert signal may be audible.
In another embodiment, an apparatus for locating an object includes an ambient light sensor, a position sensor, and an alarm circuit in communication with the ambient light sensor and the position sensor. The ambient light sensor detects an ambient light level below a predetermined threshold. The position sensor detects when the object is not in a predetermined axial orientation. The alarm circuit emits an alert signal when the ambient light level is below the predetermined threshold and the object is not in the predetermined axial orientation. The alarm may emit the alert signal if the ambient light level is below the predetermined threshold for at least a predetermined time period and/or the object is not in a predetermined axial orientation for at least a predetermined time period. The predetermined time period may be about twenty seconds.